The telecommunications industry is making ever more use of optical fibre technology, for the transmission of digital and analogue signals over extended distances. By increasing the power of the transmitted light, the distance over which a signal may be transmitted through a fibre may be increased, but this calls for equipment able to modulate high-powered light beams. For this purpose, it is known to use opto-electronic modulators, or integrated optical devices using lithium-niobate technology.
For ease of use of opto-electronic devices, it is usually convenient to provide the devices with so-called pig-tails, in the form of one or a bundle of optical fibres appropriately terminated to the component itself by the device manufacturer, in order to ensure the optimum coupling thereto. The end user then merely has to connect his optical fibre cable to the pig-tail, which is a relatively simple operation and appropriate designs of coupler are well-known for this purpose.
Advantageously, devices including opto-electronic components are located in sealed packages, hermetic or otherwise, to minimise the effect of the ambient on the component. However, in order to allow sufficient access for one or more optical fibres to be coupled to a component within an overall sealing envelope, it is necessary for that envelope to be of a significantly greater volume than that of the component to which the optical fibres are to be coupled, in order to give sufficient access to the end portions of the optical fibres whereby they may appropriately be terminated on the component.